Manufacturing precision components is done with exceptional control and either post process characterization or in situ characterization or both. This works well for smaller parts such as electronics or precision mechanical parts that require tight tolerances. For larger structures it is challenging or even not possible to make very large objects with exceptional precision. To accommodate this today, smaller parts are made with precision and then assembled and tolerance tested and adjusted until the large object meets specifications. In many cases, not all of the large object needs to be made with high precision, but there are key components within the large object and this is challenging to achieve given the overall size.
Large or very large is subjective, for example depending on the level of precision needed. Large objects that measure large fractions of a meter to many meters are very large if micron precision is required over the entire object. Methods exist to move in submicron, measure in submicron, add in submicron or subtract in submicron, but these methods are not necessarily compatible for large or very large objects.
Large motion control that can cover many meters with submicron accuracies is challenging to the point of unrealistic from a cost point of view. What is described here combines very large motion and standard adding, subtracting, cutting and polishing with very high precision requirements by utilizing real time feedback and adjustments. Using standard rigid frames or girders that can be assembled to adjustable lengths, widths and heights and putting a motion control on this structure, it is possible to put a gantry or other configuration, system together and move an object in coordinated XYZ positions under computer control. The rigid frame or girder structures can range from a large fraction of a meter to 10's of meters or even 100's of meters using standard rigid frame or girder technology. The modular approach may use standard rigid beam structure sizes. These standard sizes may be small standards for sub meter structures, medium standards for meter to tens of meter structures and large standards for more than 100 meter structures. The beam structures can be bolted together and held with supporting angle and horizontal plates to increase strengths and joints. The length, width and height of the structure will depend on the application or the object beneath it to be manufactured.
Once the structure is built, a motion system may be placed on top, this motion system can be a variety of mechanisms to move in XY and Z. The mechanisms can be belt drives, ball screw drives, linear motor drives or any mechanism that moves under computer control. The motion may be controlled with a multi-axis controller. The precision at which this system will operate will be with large tolerances that can vary from hundreds of microns for the smaller large structures to many millimeters to the very large structures. Precision manufacturing requirements can be 100 to 100,000 times more demanding.
When the large gantry system moves an object, the path for which the motion is asked to move is done with exact precision and accuracy in the computer. The reality is the motion will be significantly less accurate during the move. Feedback in linear motors motion systems utilize tape scale feedback with nanometer resolution thus providing the system a closed loop method for the object to reach the target and to do this with the most precise path during motion. The system constantly checks and adjusts its path during motion. Many meters of tape scale is expensive and must be calibrated at factory during the manufacturing process of the system and the system is not modular nor scalable.
Therefore, what is needed are improved manufacturing methods and apparatus.